Basement Playroom

I need your help!! We’re thinking about making part of our basement into a tunnel/climbing play area for our son. The floor is cement so I want thick mats or maybe mats and then a carpet on top so the floor is softer. I looked at Ruggable since they’re marketed as machine washable rugs but they’re $400 a rug 😳 and the mats we’re finding are suuuuper expensive.

Anyone have a place where they got a large number of mats at a decent price? Or any ideas for toys/tunnels/activities for the area?

Thanks in advance!!